diff --git a/include/jets/k.h b/include/jets/k.h
index b7bcaf3a1..28eec1e8f 100644
--- a/include/jets/k.h
+++ b/include/jets/k.h
@@ -89,8 +89,12 @@
     u3_atom
     u3ke_jam(u3_noun a);
 
-  /* u3ke_trip: atom to tape.
+  /* u3ke_trip(): atom to tape.
   */
     u3_noun
     u3ke_trip(u3_noun a);
 
+  /* u3kf_frog(): build %fork span.
+  */
+    u3_noun
+    u3kf_frog(u3_noun yed);
diff --git a/jets/f/fork.c b/jets/f/fork.c
index 596ab7afc..8a07ee77d 100644
--- a/jets/f/fork.c
+++ b/jets/f/fork.c
@@ -107,3 +107,12 @@
       return u3nc(c3__frog, u3kdi_tap(lez, u3_nul));
     }
   }
+
+  u3_noun
+  u3kf_frog(u3_noun yed)
+  {
+    u3_noun ret = u3qf_frog(yed);
+
+    u3z(yed);
+    return ret;
+  }
diff --git a/jets/f/ut_crop.c b/jets/f/ut_crop.c
index 8d672b1c8..d650e23c5 100644
--- a/jets/f/ut_crop.c
+++ b/jets/f/ut_crop.c
@@ -3,7 +3,7 @@
 */
 #include "all.h"
 
-#undef FROG
+#define FROG
 
 /* logic
 */
@@ -168,7 +168,7 @@
 #ifdef FROG
       case c3__frog: p_sut = u3t(sut);
       {
-        return u3qf_frog(_crop_dext_frog(van, p_sut, ref, bix));
+        return u3kf_frog(_crop_dext_frog(van, p_sut, ref, bix));
       }
 #else
       case c3__frog: p_sut = u3t(sut);
diff --git a/jets/f/ut_fish.c b/jets/f/ut_fish.c
index 8089963bf..932d0d6ec 100644
--- a/jets/f/ut_fish.c
+++ b/jets/f/ut_fish.c
@@ -3,7 +3,7 @@
 */
 #include "all.h"
 
-#undef FROG
+#define FROG
 
 /* functions
 */
diff --git a/jets/f/ut_fuse.c b/jets/f/ut_fuse.c
index e573eb54d..dc030b9d5 100644
--- a/jets/f/ut_fuse.c
+++ b/jets/f/ut_fuse.c
@@ -3,7 +3,7 @@
 */
 #include "all.h"
 
-#undef FROG
+#define FROG
 
 /* logic
 */
@@ -149,7 +149,7 @@
 #ifdef FROG
       case c3__frog: p_sut = u3t(sut);
       {
-        return _fuse_in_frog(van, p_sut, ref, bix);
+        return u3kf_frog(_fuse_in_frog(van, p_sut, ref, bix));
       }
 #else
       case c3__frog: p_sut = u3t(sut);
diff --git a/jets/f/ut_nest.c b/jets/f/ut_nest.c
index 24824c896..9dc490d79 100644
--- a/jets/f/ut_nest.c
+++ b/jets/f/ut_nest.c
@@ -3,7 +3,7 @@
 */
 #include "all.h"
 
-#undef FROG
+#define FROG
 
 /* logic
 */
diff --git a/jets/f/ut_peek.c b/jets/f/ut_peek.c
index 2e5f045d2..72d8b4fdf 100644
--- a/jets/f/ut_peek.c
+++ b/jets/f/ut_peek.c
@@ -3,7 +3,7 @@
 */
 #include "all.h"
 
-#undef FROG
+#define FROG
 
 /* logic
 */
@@ -134,7 +134,7 @@
       case c3__frog: {
         p_sut = u3t(sut);
 
-        return _peek_frog(van, p_sut, way, axe, gil);
+        return u3kf_frog(_peek_frog(van, p_sut, way, axe, gil));
       }
 #else
       case c3__frog: p_sut = u3t(sut);
diff --git a/jets/f/ut_wrap.c b/jets/f/ut_wrap.c
index e87aaa58c..6b4ff756f 100644
--- a/jets/f/ut_wrap.c
+++ b/jets/f/ut_wrap.c
@@ -3,7 +3,7 @@
 */
 #include "all.h"
 
-#undef FROG
+#define FROG
 
   static u3_noun _cqfu_wrap(u3_noun, u3_noun, u3_noun);
 
@@ -60,7 +60,7 @@
 #ifdef FROG
       case c3__frog: p_sut = u3t(sut);
       {
-        return u3qf_frog(_wrap_frog(van, p_sut, yoz));
+        return u3kf_frog(_wrap_frog(van, p_sut, yoz));
       }
 #else
       case c3__frog: p_sut = u3t(sut);